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Abstract:

Sheets of different formats, i.e. of different format lengths, are
transported in a feeding direction one behind the other; and at a certain
conveying speed, to at least two collecting drums, which have essentially
cylindrical lateral surfaces. Each of these collecting drums is driven
about an axis of rotation at a circumferential speed, which corresponds
essentially to the feeding speed of the sheets. The first incoming sheet
is secured temporarily on one of the collecting drums, while the
following, second sheet is secured temporarily on the other collecting
drum. At a suitable point in time, the two sheets secured on the
collecting drums are detached from the collecting drums and brought
together with the third fed sheet to form a sub-product or end product.

Claims:

1. A method of processing sheets of different formats, comprising:
feeding the sheets of different formats in a feeding direction one behind
the other, and at a certain feeding speed, to at least two collecting
drums, the at least two collecting drums each having essentially
cylindrical lateral surfaces, driving each of the at least two collecting
drums about a respective axis of rotation at a circumferential speed, the
circumferential speed corresponding essentially to the feeding speed of
the sheets, temporarily securing at least some of the sheets on one of
the at least two collecting drums, and detaching the secured sheets from
a first one of the at least two collecting drums and/or a second one of
the at least two collecting drums and processing the detached sheets
further.

2. The method as claimed in claim 1, wherein a plurality of the sheets
are collected to form a sheet stack on at least one of the at least two
collecting drums, and wherein the sheet stack is detached from the at
least one of the at least two collecting drums and removed for further
processing.

3. The method as claimed in claim 1, wherein the sheets of different
formats include sheets of a first format and sheets of a second format,
and the sheets of the first format are secured on the first one of the at
least two collecting drums and the sheets of the second format are
secured on the second one of the at least two collecting drums.

4. The method as claimed in claim 1, wherein the sheets of different
formats include sheets of a first format and sheets of a second format,
and a plurality of the sheets are collected to form a sheet stack on the
at least one of the at least two collecting drums, and wherein the sheet
stack is detached from the at least one of the at least two collecting
drums and removed for further processing and wherein the sheets of the
first format are secured on the first one of the at least two collecting
drums and the sheets of the second format are secured on the second one
of the at least two collecting drums.

5. The method as claimed in claim 4, wherein a plurality of the sheets of
the first format are collected on the first one of the at least two
collecting drums to form a first sheet stack and a plurality of the
sheets of the second format are collected on the second one of the at
least two collecting drums to form a second sheet stack, and wherein the
first sheet stack and the second sheet stack are detached from the
respective collecting drums and removed for further processing.

6. The method as claimed in claim 2, wherein the sheets or the sheet
stack detached from the at least one of the at least two collecting drums
are brought together with the sheets or sheet stack detached from another
one of the at least two collecting drums.

7. The method as claimed in claim 6, wherein the sheets or sheet stack
detached from the at least one of the at least two collecting drums are
positioned on the sheets or sheet stack detached from the another one of
the at least two collecting drums.

8. The method as claimed in claim 2, wherein at least the sheets which
are collected on the at least one of the at least two collecting drums to
form a sheet stack are connected to one another.

9. The method as claimed in claim 3, wherein a sheet stack detached from
the second one of the at least two collecting drums is formed from
interconnected sheets of a relatively small format, are inserted into an
interior of another folded sheet stack which has been detached from the
second one of the at least two collecting drums and is formed from sheets
of a larger format than the relatively small format.

10. The method as claimed in claim 9, wherein the larger format is a
double-sized format.

11. The method as claimed in claim 3, wherein at least one sheet of a
relatively small format detached from the one of the at least two
collecting drums is inserted into an interior of a folded sheet stack,
which has been detached from another one of the at least two collecting
drums and is formed from sheets of a larger format than the relatively
small format.

12. The method as claimed in claim 11, wherein the larger format is a
double-sized format.

13. The method as claimed in claim 2, wherein the one of the at least two
collecting drums on which a plurality of the sheets are collected, has
the sheets secured on it with edges of the sheets disposed transversely
to a feeding direction of the sheets.

14. The method as claimed in claim 2, wherein the sheets of different
formats are collected on the at least one of the at least two collecting
drums.

15. The method as claimed in claim 14, wherein sheets of another format
are wound up onto a third one of the at least two collecting drums having
an essentially cylindrical lateral surface, the sheets of another format
being secured temporarily on a circumference of the third one of the at
least two collecting drums.

16. The method as claimed in claim 1, wherein the collecting sheets are
printed by a digital printing machine, and are part of a newspaper,
periodical, brochure or the like.

17. An apparatus for processing sheets of different formats, the
apparatus comprising: a feeding device configured to feed sheets of
different formats in a feeding direction one behind the other, and at a
certain conveying speed, at least two collecting drums disposed
downstream of the feeding device, the at least two collecting drums
having essentially cylindrical lateral surfaces configured to be rotated
about an axis of rotation, securing means for temporarily securing the
fed sheets on a circumference of the at least two collecting drums, and a
drive device configured to drive the collecting drums in rotation at a
circumferential speed that corresponds essentially to the conveying speed
of the feeding device.

18. The apparatus as claimed in claim 17, further comprising a third
collecting drum, which is disposed downstream of the feeding device and
has an essentially cylindrical lateral surface configured to be rotated
about an axis of rotation, and another securing means for temporarily
securing the fed sheets on a circumference of the third collecting drum.

19. The apparatus as claimed in claim 17, wherein the securing means
comprises securing devices that operate mechanically or by means of
electrostatic forces.

20. The apparatus as claimed in claim 18, wherein the another securing
means comprises securing devices that operate mechanically or by means of
electrostatic forces.

Description:

BACKGROUND

[0001] Collecting apparatuses of this type are disclosed, for example, in
EP 1 471 022 A1 and EP 1 857 390 A1. These known collecting apparatuses
have a collecting drum which can be driven in rotation, to which the
sheets which are to be processed are fed by means of a feeding device and
on which the sheets, which are fed one behind the other, are secured
temporarily and collected to form sheet stacks. The sheets are secured on
the circumference of the collecting drums by mechanical securing devices
or by means of electrostatic forces of attraction. In order for it to be
possible to process sheets of different formats, i.e. of different format
lengths, the circumferential speed of the collecting drum and/or the
feeding speed of the feeding device has to be altered and adapted to the
varying format lengths. This requires corresponding outlay in terms of
regulating equipment.

SUMMARY

[0002] It is an object of exemplary embodiments to provide a method and an
apparatus that allow sheets of different formats that arrive one behind
the other to be processed without overly high technical outlay.

[0003] The concept according to exemplary embodiments provides for at
least two collecting drums, of which each serves to secure one or more
sheets temporarily on its circumference. The collecting drums are driven
at a circumferential speed, which corresponds to the feeding speed of the
sheets. It is thus possible for sheets of different formats or different
format lengths which arrive one behind the other, as seen in the feeding
direction, to be processed continuously without the circumferential speed
of the collecting drums and/or the feeding speed of the sheets having to
be regulated.

[0004] The one collecting drum is preferably arranged above the conveying
path for the sheets, the conveying path being defined by the feeding
device, and the other collecting drum is arranged beneath the conveying
path. The collecting drums, in this case, are driven in opposite
directions of rotation.

[0005] According to the preferred embodiments, newspapers, periodicals,
brochures and the like comprising sheets which are printed on both sides,
printing preferably having taken place in a digital printing machine, can
be produced, in particular, in a cost-effective manner. The individual
sheets of newspapers, periodicals, brochures and the like are printed
usually with four pages of text and/or images (referred to hereinbelow as
double sheets) and, following collection on the collecting cylinders, are
folded in the center. In particular newspapers, however, may also contain
sheets that are of only half the format length in relation to the other
sheets and have been printed with two pages of text and/or images
(referred to hereinbelow as single sheets). Such newspapers can be
produced particularly straightforwardly with the aid of the method
according to the invention and by means of the apparatus according to the
invention. This also applies to newspapers that contain a supplement
comprising one or more pages. In this case, the sheets of the supplement
can be collected on the one collecting drum to form a first sheet stack
and the sheets of the newspaper can be collected on the other collecting
cylinder to form a second sheet stack. If a third collecting drum is
used, it is possible to produce newspapers that comprise, as described
above, double and single sheets and contain a supplement in addition. The
sheets of the supplement here are collected preferably on the third
collecting drum.

[0006] The method and the apparatus according to the preferred
embodiments, however, can also be used to produce other products which
comprise sheets printed in a digital printing machine, e.g. calendars,
lottery tickets and the like. In the case of calendars and lottery
tickets, however, the sheets are printed only on one side.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Various exemplary embodiments of the subject matter of the
preferred embodiments will be described in more detail hereinbelow with
reference to the drawings, in which, purely schematically:

[0008] FIG. 1 shows a side view of a first embodiment of a processing
apparatus according to the invention with a cross-cutting apparatus
disposed upstream,

[0009] FIGS. 2a-2d show side views, in perspective, of various phases of a
first possible manner of operation of the processing apparatus according
to FIG. 1,

[0010] FIGS. 3a-d show side views, in perspective, of various phases of a
second possible manner of operation of the processing apparatus according
to FIG. 1,

[0011] FIGS. 4a-f show side views, in perspective, of various phases of a
third possible manner of operation of the processing apparatus according
to FIG. 1,

[0012] FIG. 5 shows a side view, in perspective and in an illustration
that is simplified in relation to FIG. 1, of a second embodiment of a
processing apparatus according to the invention,

[0013] FIG. 6 shows a side view of a phase of a possible manner of
operation of the processing apparatus according to FIG. 5, and

[0014] FIG. 7 shows a side view corresponding to FIG. 6, of a third
embodiment of a processing apparatus according to the invention.

DETAILED DESCRIPTION OF EMBODIMENTS

[0015] The first embodiment of a sheet-processing apparatus 1, which is
illustrated purely schematically in FIG. 1, has two collecting drums 2,
3, which can be driven in a rotatable manner, have cylindrical lateral
surfaces and axes of rotation designated by 2' and 3', respectively. The
collecting drum 2 here is driven in the direction of the arrow A and the
collecting drum 3 is driven in the direction of the arrow B, i.e. in
opposite directions. In the case of the present embodiment, the diameter
d2 of the one collecting drum 2 is larger than the diameter d3 of the
other collecting drum 3. The diameter d2 may be, for example, double the
size of the diameter d3. The collecting drums 2, 3 have disposed upstream
of them a feeding device 4, which defines a conveying path 5 for the
sheets 6. The collecting drums 2, 3 are located opposite one another in
relation to the conveying path 5, wherein, in the case of the present
exemplary embodiment, the collecting drum 2 with the larger diameter d2
is arranged beneath this conveying path 5. However, it is also possible
for the collecting drum 2 to be arranged above the conveying path 5 and
for the collecting drum 3 to be arranged beneath the conveying path 5.

[0016] The feeding device 4 has a number of conveying-roller pairs 7,
which are driven in a manner which is known per se (but not illustrated
specifically) such that the sheets 6 are conveyed in a feeding direction
F one behind the other to the collecting drums 2, 3 at a certain,
essentially constant feeding speed v. Instead of the conveying-roller
pairs 7, it is also possible to use other suitable conveying means, e.g.
a vacuum belt or a conveying belt provided with drivers. The collecting
drums 2, 3 are driven by means of a drive arrangement 8 (illustrated only
schematically) such that the circumferential speed u of each collecting
drum 2, 3 is essentially equal to the feeding speed v. The drive
arrangement 8 has a drive motor 9, which drives the lower collecting drum
2 via a drive element 10 (for example a drive belt or chain). This lower
collecting drum 2 is drive-connected to the upper collecting drum 3 via a
transmission 11.

[0017] A sensing device 12, for sensing the sheets 6 moving past, is
arranged along the conveying plane 5, and senses, for example, the
leading edge 6v of the sheets 6, as seen in the feeding direction F, or
markings applied to the sheets 6. The sensing device 12 is connected to a
control means (not illustrated).

[0018] The sheets 6 are severed from a continuously fed material web 14 by
means of a cross-cutting device 13 of known construction. In the case of
the exemplary embodiment shown, the sheets 6 have been printed, wherein
printing of the sheets 6 or of the material web 14 takes place preferably
in a digital printing machine. If the sheets 6 form a constituent part of
a newspaper, periodical, brochure or the like, then they are printed
usually on both sides. If the sheets are processed further to form other
kinds of product, then they may also be printed just on one side.

[0019] The two collecting cylinders 2, 3 are provided with securing means
(not illustrated), which secure the fed sheets 6 temporarily on the
circumference 2a, or 3a, of the collecting drums 2, or 3, as is
illustrated in FIG. 1 by the sheets 6' and 6''. The securing means may
be, for example, a mechanical securing mechanism, as is described in EP 1
471 022 A1, or may be formed by a securing arrangement which operates
with mechanical means or with electrostatic charging, as is disclosed in
EP 1 857 390 A1. For the description of the functioning of these known
securing means, reference is made to the aforementioned EP 1 471 022 A1
and EP 1 857 390 A1. The sheets 6 can be collected on the collecting
drums 2, 3 to form sheet stacks, which comprise a plurality of sheets 6
located one above the other, as is explained in more detail in the
aforementioned documents EP 1 471 022 A1 and EP 1 857 390 A1. However,
the sheets 6 may also be secured temporarily on the circumference 2a, 3a
of the collecting drums 2, 3 by securing means other than those mentioned
above.

[0020] Detaching elements 15 and 16 (illustrated only schematically) are
present for the purpose of detaching the sheets 6 or the sheet stacks
from the collecting drums 2 and 3, it being possible for the detaching
elements to be shifted independently of one another, and in a manner
which is not illustrated, from an inactive position into an active
position and vice versa. In the active position, the detaching elements
15, 16 detach a sheet 6 or a sheet stack from the associated collecting
drum 2 and 3 and direct the detached sheet 6 or the detached sheet stack
to a removal device 17, which may be designed, for example, in the same
way as the feeding device 4 and has driven conveying-roller pairs 18 or
other kinds of conveying means.

[0021] FIGS. 2 to 4 will be used hereinbelow to explain possible variants
in the operation of the apparatus according to FIG. 1. The
sheet-processing apparatus 1 is illustrated in simplified form in these
FIGS. 2 to 4. Thus, for example, the drive arrangement 8 for the
collecting drums 2, 3 and the cross-cutting apparatus 13 have been
omitted. Furthermore, it is assumed that the sheets 6 have been printed
on both sides. This is not absolutely necessary, however, because the
sheets 6 may also be printed just on one side or have no printing at all.

[0022] In the case of all the variants shown in FIGS. 2 to 4, sheets 6a of
a first format and sheets 6b of a second format, which differs from the
first format, are processed. The widths x of the sheets 6a, 6b are equal,
these widths running transversely to the feeding direction F, whereas the
sheets 6a are of a format length y1, extending in the feeding direction
F, which is greater than the format length y2 of the sheets 6b. In the
case of the variants shown, the format length y1 is approximately double
the size of the format length y2. The format width x and the format
lengths y1 and y2 are depicted only in FIG. 2a, but are representative of
the rest of the figures. For the sake of simplicity, a sheet 6a will be
referred to hereinbelow as a "long sheet" and a sheet 6b will be referred
to hereinbelow as a "short sheet". As illustrated in FIGS. 2 to 4, the
sheets 6a, 6b are fed to the collecting drums 2, 3 one behind the other,
as seen in the feeding direction F.

[0023] In the case of the first variant in the operation of the
sheet-processing apparatus 1, this first variant being illustrated in
FIGS. 2a to 2d, in each case two long sheets 6a and a short sheet 6b are
brought together to form an end product or interim product. FIGS. 2a to
2d show situations that follow one after the other chronologically.

[0024] As FIG. 2a shows, the short sheet 6b-1 is wound up onto the upper
collecting drum 3 and secured on the circumference thereof. According to
FIG. 2b, the short sheet 6b-1 has been wound up fully onto the collecting
drum 3, while the following, long sheet 6a-1 is wound up onto the lower
collecting drum 2 and secured on the circumference thereof. As FIG. 2c
shows, the second long sheet 6a-2 is then guided through between the
collecting drums 2, 3. This second long sheet 6a-2 is brought together,
at the same time, with the first long sheet 6a-1 and the short sheet 6b-1
such that the leading edges 6v of the three sheets 6a-1, 6a-2 and 6b-1
are aligned with one another. The sheets 6a-1 and 6b-1 are detached from
the associated collecting drums 2 and 3, respectively, by means of the
detaching elements 15 and 16, respectively. FIG. 2d illustrates how the
product 19 formed from the sheets 6a-1, 6a-2 and 6b-1 is removed in the
direction of the arrow W. The following sheets 6b-1, 6a-1 and 6a-2 are
then processed as described above.

[0025] By virtue of the sheets 6a-1 and 6a-2 located one above the other
being folded along their center line, which runs transversely to the
removal direction W, it is possible to obtain a product 19 in the case of
which the short sheet 6b-1 is located between the folded long sheets 6a-1
and 6a-2. Such a product 19 may be, for example, a newspaper or a
newspaper section, i.e. part of a newspaper, in the case of which the
long sheets 6a-1 and 6a-2 have been printed in each case with four pages
of text and/or images and the short sheets 6b-1 have been printed with
two pages of text and/or images.

[0026] FIGS. 3a to 3d show a second variant in the operation of the
sheet-processing apparatus 1, in the case of which, in the same way as
for the first variant according to FIGS. 2a to 2d, in each case a short
sheet 6b-1 and two long sheets 6a-1 and 6a-2 are put together to form a
product 19, albeit a differently constructed one.

[0027] The situations illustrated in FIGS. 3a and 3b correspond to the
situations explained with reference to FIGS. 2a and 2b. In the case of
the situation illustrated in FIG. 3b, the short sheet 6b-1 is detached
from the collecting drum 3, and brought together with the following, long
sheet 6a-1, at an earlier stage than is shown in FIG. 2b. The second long
sheet 6a-2 is then brought together with the sheets 6a-1 and 6b-1 located
one upon the other (FIG. 3c). The operation of positioning the sheets
6a-1, 6b-1 and 6a-2 one upon the other likewise takes place such that the
leading edges 6v thereof are aligned with one another. The situation
shown in FIG. 3d corresponds to the situation according to FIG. 2d, with
the exception that the product 19 has been put together differently and
comprises the short sheet 6b-1 located between the long sheets 6a-1 and
6a-2.

[0028] In the case of the third variant in the operation of the
sheet-processing apparatus 1, this third variant being illustrated in
FIGS. 4a to 4f, in each case three short sheets 6b and two long sheets
6a, which are fed in the feeding direction F one behind the other to the
collecting drums 2, 3, are brought together first of all to form interim
products and then to form an end product. FIGS. 4a to 4f show, in the
same way as the illustrations of FIGS. 2a to 2d and 3a to 3d, situations
that follow one after the other chronologically.

[0029] As FIGS. 4a and 4b show, the short sheets 6b-1 and 6b-2 are wound
up onto the upper collecting drum 3, and secured on the circumference
thereof, such that the sheets 6b-1, 6b-2 are aligned by way of their side
edges. The first short sheet 6b-1 here revolves along with the collecting
drum 3 more than once. The third incoming short sheet 6b-3 is brought
together with the sheets 6b-1 and 6b-2, now detached from the collecting
drum 3, such that all three short sheets 6b-1, 6b-2 and 6b-3 are aligned
with one another by way of their side edges (FIG. 4b).

[0030] As FIG. 4c shows, the short sheets 6b-1, 6b-2, 6b-3, which are
located one above the other and form a first sheet stack S1, are removed
in the direction of the arrow W, while the long sheet 6a-1 is wound up
onto the lower collecting drum 2 and secured on the circumference
thereof. The next incoming long sheet 6a-2 is brought together with the
sheet 6a-1, now detached from the collecting drum 2, such that the two
long sheets 6a-1 and 6a-2 are aligned with one another by way of their
side edges. The short sheets 6b-1, 6b-2 and 6b-3 of the first sheet stack
S1 may be connected to one another along the longitudinal edge designated
by L, this being done preferably by means of an adhesive, which has been
applied to the sheets 6b-1, 6b-2, 6b-3, for example, as they are
collected on the collecting drum 3. In the case of the production of
newspapers, periodicals, brochures and the like, the sheets 6b-1, 6b-2,
6b-3 of the sheet stack S1, however, are connected to one another usually
along the later folding line 21, which extends in the removal direction
W.

[0031] In the case of the situation shown in FIG. 4d, the first sheet
stack S1, formed from the short sheets 6b-1, 6b-2, 6b-3, has been folded
along the folding line 21 (see FIG. 4c). In this FIG. 4d, the resulting
folding edge is designated by 21a and the folded sub-product is
designated by 20a. As FIG. 4d also shows, the long sheets 2a-1 and 2a-2,
collected on the collecting drum 2 to form a second sheet stack S2, have
been detached from the collecting drum 2 and form a second sub-product
20b. The sheets 2a-1 and 2a-2, which are located one above the other and
are aligned with one another, are folded a first time along a first
folding line 22 (see FIG. 4d), which runs transversely to the removal
direction W, as has been illustrated in FIG. 4e, in which the resulting
folding edge is designated by 22a.

[0032] In a later phase, the once-folded sub-product 20b is folded a
second time, to be precise along a second folding line 23 (see FIG. 4e),
which runs at right angles to the first folding edge 22a. The
twice-folded sub-product 20b is positioned over the other, once-folded
sub-product 20a, as is illustrated on the left-hand side of FIG. 4f. In
this FIG. 4f, the resulting end product is designated by 19 and the
second folding edge of the sub-product 20b is designated by 23a.

[0033] As FIGS. 4c to 4f show, the successive sheets 6b-1, 6b-2, 6b-3,
6a-1 and 6a-2 are processed in the manner described above to form the
next sub-products 20a and 20b and then to form the next end product 19.
FIG. 4f, which corresponds to the illustration of FIG. 4c, shows the
first sheet stack S1' for the next sub-product 20a.

[0034] The end product 19 shown in FIG. 4f may be a newspaper comprising a
supplement (magazine, brochure or the like) inserted into the actual
newspaper. In this case, the sub-product 20a forms the supplement and the
sub-product 20b forms the actual newspaper. All of the sheets 6b-1, 6b-2,
6b-3 of the sub-product 20a (supplement) and the sheets 6a-1, 6a-2 of the
other sub-product 20b (newspaper) have been printed with four pages of
text and/or images.

[0035] As an alternative to the exemplary embodiment shown, it is also
possible, in the further processing of the sheet stacks S1 and S2, for
the sub-product 20a not to be folded, for the other sub-product 20b to be
folded only once about the folding line 22, and for the non-folded
sub-product 20a, i.e. the sheet stack S1 (FIG. 4c), to be inserted into
the once-folded sub-product 20b (see FIG. 4e).

[0036] FIG. 5 shows a side view, in perspective (corresponding to the
illustrations in FIGS. 2 to 4), of a second embodiment of a
sheet-processing apparatus 1' according to the invention. The
sheet-processing apparatus 1' in this FIG. 5 is shown in simplified form
in relation to the illustration of FIG. 1. This sheet-processing
apparatus 1' according to FIG. 5, with the exception of the diameters d2,
d3 of the collecting drums 2, 3, corresponds to the sheet-processing
apparatus 1 shown in FIG. 1, wherein certain components, for example the
drive arrangement 8, the sensing device 12 and the cross-cutting
apparatus 13, have been omitted from FIG. 5. For parts that correspond to
one another, the same designations have been used in FIGS. 1 and 5.

[0037] As explained above, the sheet-processing apparatus 1' illustrated
in FIG. 5 differs from the sheet-processing apparatus 1 according to FIG.
1 by a different ratio between the sizes of the collecting-drum diameters
d2 and d3. Thus, in the case of the sheet-processing apparatus 1' shown
in FIG. 5, the two collecting-drum diameters d2 and d3 are equal. This
increases the possible uses of the sheet-processing apparatus 1', because
the incoming sheets 6, irrespective of their format, can be fed to the
lower collecting drum 2 or the upper collecting drum 3.

[0038] FIGS. 5 and 6 show a variant in the many possible manners of
operation of the sheet-processing apparatus 1'. In the case of this
variant shown, the sheets are fed to the collecting drums 2, 3, by the
feeding device 4, in the following order: at the beginning of processing,
two short sheets 6b-1 and 6b-2 followed by two long sheets 6a-1 and 6a-2
and then in each case a short sheet 6b-3 and, once again, two long sheets
6a-3 and 6a-4. In the case of the situation shown in FIG. 5, a product 19
has been produced from the long sheets 6a-1 and 6a-2, which are located
one upon the other, and the first incoming short sheet 6b-1. This means
that this product 19 is formed from sheets 6a, 6b which are not fed
directly one behind the other to the collecting drums 2, 3. In order for
such a product 19 to be produced, it is necessary for the lengths of the
circumference of the collecting drums 2, 3 to be equal to, or greater
than, double the format length y2 (see FIG. 2a) of the short sheets 6b-1,
6b-2, 6b-3. Processing of the sheets 6a, 6b, which are fed by the feeding
device 4, proceeds as follows:

[0039] The two first short sheets 6b-1 and 6b-2 are wound up onto the
circumference of the upper collecting drum 3, while the first incoming
long sheet 6a-1 is wound up onto the circumference of the lower
collecting drum 2. As the second long sheet 6a-2 runs through between the
collecting drums 2, 3, the first short sheet 6b-1 is detached from the
collecting drum 3 and the first long sheet 6a-1 is detached from the
collecting drum 2, and these are brought together with the second long
sheet 6a-2. The short sheet 6b-1 here is positioned on the long sheet
6a-2 from above, and the long sheet 6a-1 is positioned on the long sheet
6a-2 from beneath, such that the sheets 6b-1, 6a-2 and 6a-1 are aligned
with one another by way of their leading edges.

[0040] In a corresponding manner, the short sheet 6b-2 and the long sheets
6a-3 and 6a-4 fed thereafter are used to produce a product 19' in the
case of which the short sheet 6b-3 rests on the long sheet 6a-4, which
for its part rests on the other long sheet 6a-3 (see also FIG. 6, which
serves to clarify this manner of operation). In order to produce this
product, the short sheet 6b-2 is first of all retained temporarily on the
upper collecting drum 3 and then positioned on the long sheet 6a-4, while
the other long sheet 6a-3, which is first of all retained temporarily on
the lower collecting drum, is positioned on the sheet 6a-4 from beneath.
The third short sheet 6b-3 is secured temporarily on the circumference of
the upper collecting drum 3.

[0041] In the case of a variant in the above-described manner of
operation, the collecting drums 2, 3 are fed always two short sheets 6b-1
and 6b-2 followed by two long sheets 6a-1 and 6a-2, to produce products
19, 19' in the case of which, as shown, in each case long sheets 6a-1,
6a-2 and 6a-3, 6a-4 and short sheets 6b-1 and 6b-2, respectively, rest
one upon the other. In the case of this variant, the first short sheet
6b-1, as described, is brought together with the following long sheets
6a-1 and 6a-2, while the second short sheet 6b-2 is secured on the upper
collecting drum 3 until it can be brought together with the next incoming
long sheet 6a-3 and 6a-4.

[0042] As the use example explained with reference to FIGS. 5 and 6 shows,
the sheet-processing apparatus 1' according to FIG. 5 can produce
products which comprise sheets 6a, 6b which are not located immediately
one behind the other in the sheet stream fed to the collecting drums 2,
3. This is, of course, also possible using a sheet-processing apparatus 1
according to FIG. 1.

[0043] A third embodiment of a sheet-processing apparatus 1'' according to
the invention will be described hereinbelow with reference to FIG. 7, the
illustration of which corresponds to that in FIG. 6. This
sheet-processing apparatus 1'' is illustrated in simplified form in
relation to the sheet-processing apparatus 1 shown in FIG. 1 and differs
from the latter by the addition of a third collecting drum 25, which has
an essentially cylindrical lateral surface and can be rotated about an
axis of rotation. Otherwise, the sheet-processing apparatus 1''
corresponds to the sheet-processing apparatus 1 according to FIG. 1.
Parts that correspond to one another have the same designations in FIG. 7
as in FIGS. 1 to 6. The diameter of the third collecting drum 25 may be
equal to, or different from, the diameters d2, d3 of the collecting drums
2, 3. The provision of a third collecting drum 25 makes it possible to
produce end products which differ from the end products 19 which can be
produced in FIGS. 1 to 5. A possible manner of operation of the
sheet-processing apparatus 1'' will be described hereinbelow with
reference to FIG. 7.

[0044] As FIG. 7 shows, the collecting drums 2, 3, 25, as seen in the
conveying direction F, are fed in the first instance three sheets 6c-1,
6c-2 and 6c-3 of a third format, which, for the sake of simplicity, will
be referred to hereinbelow as "additional sheets". These additional
sheets 6c differ in format from the formats of the long sheets 6a and of
the short sheets 6b. In the sheet stream fed to the collecting drums 2,
3, 25, the additional sheets 6c-1, 6c-2 and 6c-3 are followed by a short
sheet 6b-1 and two long sheets 6a-1 and 6a-2.

[0046] The additional sheets 6c-1 and 6c-2 are wound up onto the third
collecting drum 25, and secured temporarily on the circumference thereof,
in the manner already described with reference to FIGS. 2 to 6. The
additional sheets 6c-1, 6c-2 are then detached from the collecting drum
25 and positioned on the third additional sheet 6c-3 as it moves past the
third collecting drum 25. The resulting sheet stack is guided through
between the collecting drums 2, 3 and removed for further processing.
This sheet stack is illustrated on the left-hand side of FIG. 7 and
designated by S2. In this sheet stack S2, the additional sheets 6c-3,
6c-2 and 6c-1 are located one above the other in this order such that
they are aligned with one another by way of their side edges. The
following sheets 6b-1, 6a-1, 6a-2 are guided past the third collecting
drum 25. The short sheet 6b-1 is wound up onto the upper collecting drum
3 and the following, first long sheet 6a-1 is wound up onto the lower
collecting drum 2. The second long sheet 6a-2 is guided through between
the collecting drums 2, 3 and, at the same time, brought together with
the short sheet 6b-1, detached from the collecting drum 3, and the first
long sheet 6a-1, which is detached from the other collecting drum 2, as
has been explained in more detail with reference to FIG. 2. The short
sheet 6b-1 here is positioned on the second long sheet 6a-2 from above
and the first long sheet 6a-1 is positioned thereon from beneath. The
resulting sheet stack is removed for further processing. This sheet stack
is illustrated on the left-hand side of FIG. 7 and designed by S1. In
this sheet stack S1, the sheets 6a-1, 6a-2 and 6b-1 are located one above
the other in this order such that they are aligned with one another by
way of their side edges.

[0047] In the case of a preferred use example, the interim product 26
formed by the sheet stack S1 is a newspaper comprising two double pages,
i.e. the long sheets 6a-1 and 6a-2, and a half-format, single page, i.e.
the short sheet 6b-1. The double pages (sheets 6a-1 and 6a-2) have been
printed with four pages of text and/or images, and the single page (sheet
6b-1) has been printed with two pages of text and/or images. The other
interim product 27, formed by the sheet stack S2, is a supplement
(periodical or brochure), preferably a tabloid. An end product is
obtained by virtue of the interim product 27 (supplement) being inserted
into the once-folded (as described with reference to FIG. 4d) interim
product 26 (newspaper).

[0048] In addition to the aforementioned advantages and preferred variants
of the method according to the invention and of the apparatus according
to the invention, further particular aspects of the present invention
will be pointed out hereinbelow.

[0049] In each case either just a single sheet 6 or a plurality of sheets
6 located one above the other, and forming a sheet stack S, can be
secured (collected) on each of the collecting drums 2, 3, 25. It is
possible here for a sheet stack S to be formed from sheets 6 of the same
format or from sheets 6 of different formats. If the length of the
circumference allows it, two or more sheets 6 or sheet stacks S can be
secured at the same time on the circumference of a collecting drum 2, 3,
25, as is illustrated in FIG. 5 for the collecting drum 3.

[0050] In the case of the exemplary embodiments described with reference
to FIGS. 2 to 7, the sheets 6 are brought together such that, in the
resulting product 19, the sheets 6 are aligned with one another by way of
their leading edges 6v. However, it is also possible for the sheets 6,
when brought together, to be aligned with one another by way of their
trailing, rear edges or by way of one of their side edges, extending in
the feeding direction F. In addition, it is, of course, also possible to
dispense altogether with alignment of the sheets 6.

[0051] The sheets 6 fed in a stream to the collecting drums 2, 3, 25 can
also be used to produce, one after the other, products 19 which differ
from one another in terms of composition, e.g. in terms of the number of
sheets 6 or of the combination of sheets 6 of different formats.

[0052] The sheets 6 can be secured optionally on the any one of the
collecting drums 2, 3, 25. It is not imperative for all the sheets 6 to
be wound up onto the circumference of the collecting drums 2, 3, 25,
because certain sheets 6 are guided through between the collecting drums
2, 3 and/or directed past the collecting drum 25, as has been explained
with reference to FIGS. 2, 3, 5 and 7.

[0053] The sheets 6 fed to the collecting drums 2, 3, 25 may also have
more than two or three different formats. The sheets 6 of different
formats may be of the same width b and different format lengths y or the
same format length y and different widths b.

[0054] Instead of, as described, a material web 14, from which the sheets
6 are then severed, being printed in a digital printing machine, it is
also possible for the sheets to be printed directly in the digital
machine.

[0055] The sheets 6 may be made of paper, plastics material, a textile
material or any other suitable material.

[0056] A preferred area of use of the method according to the invention
and of the sheet-processing apparatus according to the invention is the
production of newspapers, periodicals, brochures and the like from sheets
of different formats printed in a digital printing machine. However, the
method according to the invention and the apparatus according to the
invention can also be used to produce other products comprising sheets
printed in a digital printing machine, e.g. calendars, lottery tickets
and the like.